staging: wilc1000: remove typedef from tstrWILC_UsrScanReq

This patch removes typedef from the struct tstrWILC_UsrScanReq with
related comments and renames it to user_scan_req.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>